The disclosure is based on a sensor assembly for ascertaining the path of a moved component.
Rotational speed sensors and position sensors are known from the prior art and it is possible for said rotational speed sensors and position sensors to identify and evaluate a rotational movement or a change in position by means of ascertaining a corresponding change in a magnetic field. In general, known magnetic sensors are used that can be embodied depending upon their use and area of application as Hall sensors, AMR sensors, GMR sensors, TMR sensors or generally as xMR sensors and can be used by way of example for controlling motors or in transmission systems or driving dynamics systems in motor vehicles. In the case of the magnetic circuit design of such sensor assemblies for measuring the path and angle in a magnetic manner by means of ascertaining a change in the magnetic angle over the path or angle, it is necessary to fulfill requirements of the sensitive elements or evaluating components (ASICs) in relation to maintaining a defined flux density region. In order to be able to measure long paths (>20 mm) with a high degree of precision, generally at least two moving magnets are used when measuring the path or angle by means of ascertaining a change in a magnetic angle over the path or angle. These magnets provide a common magnetic field having as large as possible (<360°) a change in magnetic angle over the actuating path or an actuating angle and simultaneously a defined magnetic flux density. That means that it is necessary to integrate two relatively large magnets on the moving part of an application which is not always possible because of the available construction space or is only possible with complex and thereby expensive constructions and strong and thereby likewise expensive magnets.
It is essential for the sensitive measuring element in use to ascertain the revolving or rotating magnetic field vector. This revolving or rotating movement of the magnetic field vector is ascertained by means of the sensitive measuring element that can be part of an ASICs (application specific integrated circuit). This occurs by way of example in the case of a two-dimensional or three-dimensional Hall sensor by means of indirectly ascertaining the angle by way of an arc-tangent function of the magnetic flux density that is directed.
DE 10 2009 055 104 A1 discloses by way of example a magnetic field sensor assembly for ascertaining the path of moved components, in which spatial components of the magnetic field of a magnet system on the moved component change in their direction over the path that is to be ascertained and as a consequence it is possible to accordingly detect their position with respect to a fixed sensor. At least one magnet is located on the component that moves in a linear manner and in a further degree of freedom, said magnet being a component of the magnetic system or another magnetic component whose outer circumference is allocated in a predetermined spacing lying opposite at least one fixed sensor that is sensitive to the magnetic field direction, wherein the preferred direction of the magnetic field of the magnet is aligned in a predetermined angle with respect to the path between zero and 90° of the moved component.